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BAND SAW MILL.

No. 338,170.. Patented Mar. 16, 1886.

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ALBERT F. GRIS\VOLD AND HENRY R. BARNHURST, OF ERIE, PA.

BAND-SAW MILL.

SPECIFICATION forming part of Letters Patent No. 338,170, dated March 16, 1886.

Application filed November 23, 1885.

To aZZ whom, it may concern:

Be it known that we, ALBERT F. GniswoLn and HENRY It. Bnnnnnnsrr, citizens of the United States, residing at Erie, in the county of Erie and State of Pennsylvania, have invented certain new and useful Improvements in Band-Saw Saw-Mills; and we do hereby declare the following to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to that type of sawmills in which a band-saw is used; and it consists in certain improvements in the construction thereof, as will be hereinafter fully set forth, and pointed out in the claims.

In saw-mills of the type above named the bandsaw runs on two large band-wheels, one of which-the lower, usnally-is on the driv ing-shaft of the mechanism, and the other is driven by the band-saw acting as a belt. li e will hereinafter refer to these wheels as the driving-wheel and the driven wheel, respectively. \Vhenever the saw commences to act upon a log, or when it encounters a hard ward-moving sidewill of course be strained taut, while the other side will be as slack as the length of the saw will permit. In large saw-mills used for sawing logs these wheels are very large, and, though made as light as possible, they have considerable weight, and consequently the inertia of the driven wheel is considerable, and when a checking of the speed of the driving-wheel occurs the driven wheel will not respond at once to the change, but will by its momentum continue to move at the same speed it was moving. This action will, momentarily, change the driven wheel into a driving-wheel, so far as the saw is concerned, and the slack side of the saw will be suddenly drawn taut and the taut side be slackened. The effect of this action is often Serial No. 183,756. (No model.)

a breakage of the saw, and always an uneven saw-kerf in the log or cant.

To obviate the above difficulty builders of this type of mill have provided various devicessnch, for example, as wings or fans on the spokes of the driven-wheel, or driving other machinery in the mill from a pulley on the shaft of the driven wheel. Such devices are intended to afford sufficient resistance to the rotation of the driven wheel to prevent it moving by its momentum when the speed of the driving-wheel is slackened; but such devices are objectionable.

The plan of putting fans on the spokes of the driven wheel is objectionable, because if the fans are large enough to effect the result desired, too great a current of air is created at points where the attendants must stand.

The plan of driving other machinery has many objections, the chief one being that if the machinery is used to do any work it must necessarily require more power at one time than another, and hence the resistance on the driven wheel will be variable; and another important objection is that such mechanism cannot be compact.

One of the principal objects we aim to attain is to contain the resisting mechanism within or upon the frame-work containing the driven wheel, so that all the parts may move as one in adjusting the driven wheel to the saw. To make this point clear it should be stated that the driven band-wheel has to be movable vertically and adjustable at diii'erent distances from the driving-wheel,so as to properly mount saws of different lengths, and also to give the saws the proper degree of tension; hence it is that the mechanism which is to serve as a load on the driven wheel should be mounted with it on a common frame-work, so as to laterally.

The means we employ to give the necessary resistance is the action of two friction-disks upon each other, and we mount them and the gearing by which they are made to act on the same frame-work that the driven wheel is mounted on. Of course the form of the disks may be varied greatly, and the gearing making them act upon each other as the driven wheel revolves may be greatly variedin type.

move with it when it is adjusted vertically or It would be practically impossible for us to here illustrate all the various constructions that could be made by any skilled mechanic and effect good results. The construction we consider the best and most practical is shown in the accompanying drawings, and consists of cup-frictions rotated in the same direction at varying speed. Such a construction we believe will give the required resistance with the least danger of heating the impinging surfaces too high, of any equally cheap, compact, and practical construction.

The accompanying drawings illustrate our invention as follows: Figure 1 is a front elevation, and shows the top part of the sup porting-column A, the framework A, which is mounted to slide vertically in the fork of said column, on which the driven wheel shaft B, is journaled, the extension A of said frame work, which supports the resisting mechanism; and also shows the gearing of the said resisting mechanism. Fig. 2 is a side elevation of the same parts, the cup-frictions being in section to show their form.

The parts and their construction are as follows: The column A and the sliding framework A and the method of mounting the bandwhcel B on said sliding frame is as commonly constructed. The frame-work A has a bracket-extension, A for supporting the gearing of the resisting mechanism. The shaft B of the driven wheel B is extended from its journalbox over the bracket-extension A and two spur-gears of different diameters, I) If, are secured thereon. In the frame-work below them are journaled two other spurgears, c c, of different diameters, which are driven, respectively, by the gears b and b and they drive, respectively, the cup-frictions O G. A sprin S, is provided to keep the cup-frictions set together. It will at once be seen that the fric tion-cups revolve in the same direction, but at different speed, and hence move upon each other and resist theaetion of the band-wheel B.

Vhile it is desirable that the resisting device be mounted on the frame-work on which the driven wheel is mounted it is not essential to the use of our resisting device, for it may be mounted at a distance from said shaft, and run by belts or other gearing from the shaft B.

"\Vhat we claim as new is 1. In a band-sawsaw-mill, the combination, with the shaft of the driven band-wheel and the vertically-movable frame in which it is journaled, of a rotating resisting device and gearing for actuating the same,which is m0unted on said vertically-movable frame and actuated from said band-wheel shaft, substantially as set forth.

2. In a band-saw saw-mill, the combination, with the shaft of the driven band-wheel and the vertically-movable frame-work in which it is journaled, of friction-disks and gearing for causing said disks to act upon each other, mounted on said vertically movable frame and actuated from said band-wheel shaft, substantially as set forth.

3. In a band-sari saw-mill, the combination, with the shaft of the driven band-wheel, and the vertically-movable frame in which it is mounted, of friction-disks and gearing for causing said disks to revolve at different speed in the same direction, mounted on said vertically-movable frame and actuated from said band-wheel shaft, substantially as set forth.

4. In a band-saw saw-mill, the combination, with the shaft of the driven band-wheel, of a resisting device consisting of two frictiondisks and gearing for moving the same upon each other, which is operated from said bandwheel shaft, substantially as set forth.

In testimony whereof we affix our signatures in presence of two witnesses.

ALBERT F. GRISXVOLD. HENRY It. BARNHURST. \Vitn esses:

J NO. K. HALLOOK, Boer. H. PORTER. 

